"It's life Jim but not as we know it" - The Hamelin Pool Stromatolites

Evidence of some of the earliest life on earth is found in rocks which date back 3.7 billion years and contain the fossilised remains of structures known as stromatolites. Remarkably in a very few places in the world living stromatolites still exist and the largest and most diverse selection of all are in Western Australia at Hamelin Pool.

In reality a stromatolite is not a single organism, it is in fact a structure which is created by a multitude of living organisms, especially cyanobacteria. These microscopic organisms along with others, form biofilms (microbial mats) which trap, bind and cement sedimentary grains creating layers on which more biofilms can grow. These in turn trap more sedimentary grains, creating more layers, and so it goes on, layer upon layer, so that over time the stromatolite structures form. They are as close as it gets to living rocks.

Perhaps stromatolites greatest claim to fame is the part they played in putting oxygen into the earth's atmosphere 3.7 billion years ago. When they first appeared there was virtually no oxygen in the atmosphere, but because they are photosynthetic they take carbon dioxide and water to produce carbohydrates, and in doing this they liberate oxygen. Largely thanks to this, the levels of oxygen in the earth's atmosphere rose high enough to allow other life on earth to exist. The bad news for the stromatolites was that some of this new life then consumed the cyanobacteria, thus reducing the numbers of stromatolites.

They can exist in the modern world only in extreme conditions. High levels of salinity combined with the tidal nature of Hamelin Pool and extreme temperatures often exceeding 45 degrees celcius in summer creates an environment so harsh that virtually no other plants or animals can survive, thus allowing the stromatolites at Hamelin Pool to grow undisturbed.

Ningaloo Reef, Western Australia

The opportunity to visit the Ningaloo Reef in Western Australia was one of the main attractions when planning this particular holiday. It's what is known as a fringing reef which means that it occurs close to shore and in fact the Ningaloo reef is considered to be one of the most accessible reefs in the World because in many places you can simply swim out to it from the shore.

Some would argue that it's more impressive even than the Great Barrier Reef, but though I've now been to both it's unfair of me to make a comparison. Not a great snorkeler, I'm also a poor swimmer and certainly I'm no diver, all of which makes it difficult for me to truly experience coral reefs and even more difficult therefore to make comparisons. However, armed with a brand new snorkel fitted with prescription lenses I gave it a go, and there was always the fall back of a glass bottom boat! Josh on the otherhand is a much better swimmer and snorkeler and even better he has an underwater camera with which he was able to take the first 10 or so of the photographs on this post.

Lake Monger, Perth

Lake Monger is next to Herdsman and though not as impressive it still has a decent array of species and is better for some species such as hoary-headed grebe and blue-billed duck. When I last visited the lake in July last year it was the middle of the Australian winter and I counted an impressive 300 blue-billed ducks, but today most of these birds had dispersed and I managed only about 20 birds of which all bar one were males. What I didn't realise until today was that the species breeds at Lake Monger and the highlight of the visit was finding this female with about six fluffy chicks. Really cute!

Once more to Herdsman in the rain

Herdsman is a fabulous place to visit if you have half a day to kill in Perth as I did today, and just like two weeks ago I finally managed to photograph a hard to get species. I was walking back to the car park and spotted a buff-banded rail walking amongst the long grass. At first I could only see its head and even that would disappear for periods, so I just stood still and waited. Eventually the bird emerged fully from the long stuff and started walking around on the shorter grass, and to my disbelief given how hard they can be to see at times, it seemed quite unconcerned by my presence and allowed me to take some reasonable photos. About 10 minutes later I then spotted a second bird, this one with a chick, and they were walking around the front garden of one of the nearby houses!

Lake Thetis and the Cervantes Stromatolites

Just outside Cervantes there is a small pool in which the conditions are so saline and so extreme that stromatolites can grow. This is nothing like the scale of those at Hamelin Pool, yet stromatolites none the less. See the post from Hamelin Pool for a fuller explanation of what stromatolites are

The Pinnacles Desert, WA

Emu crossing the Pinnacles Desert. I'm not sure how these birds manage to survive out here but they do and often in much harsher conditions than this. Emus are all across Australia, only really absent from heavily forested regions.

Hutt Lagoon and Kalbarri NP, WA

The algae in Hutt Lagoon turn the waters pink in certain lights and make it a popular tourist stop for anybody in the region of Kalbarri National Park. The lagoon also attracts quite large numbers of stilts, both banded and white-headed, which allow decent photo opportunities of mainly white birds in pink water!

The dugongs of Monkey Mia

Photo: Mother and calf dugong.

The Shark Bay World Heritage Area covers around 2.2 million hectares and is about a 10 hour drive north of Perth, best accessed from Monkey Mia. There are many reasons for its listing as a World Heritage Area, one of which are the stromatolites at Hamelin Pool which I will discuss later in a seperate post. Another reason is that it is home to a large population of dugongs which feed on the seagrass in the bay just offshore. Dugongs are neither whales or dolphins, they are in fact related to manatees, and are often called seacows, with Shark Bay having around 10% of the world population, about 10,000 animals. The holes you can see are not blow holes because the species does not have blow holes. They are in fact the dugongs nostrils and as you might expect, the eyes are behind the nostrils as you can see more clearly in the photo below.

Today we managed to see about 15 of these wonderful creatures, as well as about 10 Indo-Pacific bottlenose dolphins and a few awesome loggerhead turtles.

Western Grasswrens at Monkey Mia, WA

The enigmatic grasswrens are usually high up on any birders most wanted list when they visit Australia, but they are always difficult birds to connect with, mainly because they usually inhabit very remote and hard to get to places. You can't just fly to Sydney and see them during a walk around the botanic gardens!

Not surprising therefore that I was delighted to see several western grasswrens at Monkey Mia today. Also today lots of waders including Terek sandpiper, great knot, red-necked stint and red-capped plover, and terns were again well represented, with at least 40 Caspian as well as a few each of crested and lesser crested and fairy terns, the latter being a new tern for the holiday list.

A walk along the beach at Coral Bay, WA

The walk from Five Fingers Reef, through Coral Bay, to the headland north of Shark Lagoon is about 15km but well worth the effort, with turquoise seas and fine white sand beaches at the base of large sand dunes, the scenery is just stunning. Terns dominate here and during our stay I managed to see eight different species of tern of varying shapes and sizes as you can see from this photo!

A walk along the beach at night, Cape Range

Last night we had a walk on a remote beach at Cape Range in Western Australia, which is about 20km from Exmouth, the nearest town. It was a full moon and we came across a female green turtle egg laying on the beach. To give you an idea of the size of this magnificent animal, it's about 1.5m from nose to tail and weighs approximately 160kg (25 stone). The hole in the sand which it was digging is around 2m diameter. Yet another amazing experience on this holiday. We didn't stay with it too long not wanting to disturb it, and fortunately we had red light on our head torches which causes minimum disturbance to nocturnal animals. All of these photos were taken on my phone which is a Google Pixel 4a, on the night setting.